Polyvinyl ethers having silicon-containing functional groups or atomic groups at the end and process for production thereof

ABSTRACT

Disclosed is a technology for the production of polyvinyl ethers having a reactive silicon-containing functional or atomic group at the terminal thereof. The polyvinyl ether as expressed by the formula (VII) is prepared by allowing, in the presence of a catalyst composed of a polynuclear ruthenium-carbonyl complex in which carbonyl groups coordinate with two to four ruthenium atoms, a vinylether compound expressed by the formula (III) to react with a silane compound expressed by the formula (IV). In the formulae, R 1 , R 2  and R 3  each represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms, R 4  represents an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, or a silyl group, and X 1 , X 2  and X 3  each represents a hydrogen atom, a halogen atom, an amino group, an alkyl group, an alkoxy group, a thioalkyl group, an alkylamino group, an aryl group, an arylamino group, an aralkyl group a vinyl group, or a heterocyclic group.

TECHNICAL FIELD

The present invention belongs to the technical field of polymericmaterials, and particularly relates to polyvinyl ethers having asilicon-containing functional or atomic group at the terminal thereofand a method for producing the same.

BACKGROUND ART

Polyvinyl ethers are industrially important materials as they are usedas materials for electronic parts, lubricants, adhesives and so on.Realization of the ability to provide a polyvinyl ether with a reactivesilicon-containing functional group, such as silyl group or siloxygroup, at the terminal thereof, can be expected to lead to the creationof a variety of novel functional materials, by combining anothercompound (molecule) with the polyvinyl ether via such functional groupor by replacing the functional group with another functional group.However, no concrete means are available for obtaining such a polyvinylester. More specifically, although there have hitherto proposedpolymerization reactions of various types of vinyl ethers using a Lewisacid, in the broad sense of the word including protonic acids, carbonylion salts, metal halides and the like, no examples are found expresslyreporting on a polymer having a functional group such as silyl group orsiloxy group at the terminal thereof.

As a relevant polymerization including polymerization of a vinyl ether,there can be cited a cationic polymerization in which chlorosilane and ametal halide (Hg₂Cl₂) are used (Kageura et al., J. Polym. Sci., 11, 1109(1972)). In the process described in this paper, no reference is made tothe terminal of the polymer. Furthermore, use of the chlorosilaneencounters a handling problem because chlorosilane easily decomposes dueto hydrolysis, thereby producing hydrochloric acid. More specifically,while a hydrosilane having functional groups such as one to three alkylgroups attached to the silicon atom has good handling property in apolymerization reaction, it exhibits a polymerization activity only whenactivated with a transition metal catalyst.

Examples of the polymerization reactions of vinyl ethers using ahydrosilane activated by a transition metal catalyst are very few andfound only in a report in which a cobalt complex (dicobalt octacarbonyl)is used (Crivello et al., J. Polym. Sci. A., 30, 31-39 (1992)), and in apatent application relating to an invention of a polymerization catalystprimarily composed of platinum for vinyl ethers (Japanese PatentApplication Publication No. 17244/1994).

The paper of Crivello et al. relates to a polymerization processincluding an isomeric reaction of an allyl ether to a vinyl ether. Withregard to the polymerization of the vinyl ether, while the molecularweight and molecular weight distribution of the polymer produced are setout, only one working example is given and no elucidation is foundregarding the molecular structure of the polymer, including its terminalstructure. In the above-mentioned patent application, nothing whatsoeveris said regarding either the terminal structure of the polymer or themolecular weight and the molecular weight distribution of the polyvinylether.

The object of the present invention is to provide a polyvinyl etherhaving a silicon-containing functional group or atomic group, such assilyl group or siloxy group, at the terminal thereof and also a methodfor producing such polyvinyl ether as a novel polyvinyl ether.

DISCLOSURE OF THE INVENTION

The present inventors previously achieved inventions relating to theproduction of a polyether by the polymerization of a cyclic ether andalso the production of a silalkylenesiloxane by the polymerization of acyclic siloxane, using a catalyst composed of a polynuclearruthenium-carbonyl complex, a new type of polymerization catalyst whichis totally different from the conventional polymerization catalysts(Japanese Patent Application Publication No. 59021/2001:PCT/JP00/07531).

The present inventors have made continued studies and accomplished thepresent invention based on a surprising finding that the polynuclearruthenium-carbonyl complex when used in combination with a specificsilane compound serves as a highly-active catalyst for thepolymerization of a general type of (i.e. non-cyclic) vinyl ether aswell as that of the cyclic vinyl ether, thereby enabling the productionof the above-mentioned objective polyvinyl ether.

Thus, according to the present invention, there is provided a polyvinylether composed of a repeating unit represented by the following formula(I) and having a hydrogen atom at one terminal thereof and asilicon-containing functional group or atomic group represented by thefollowing formula (II) at the other terminal thereof:

In the formula (I), R¹, R² and R³ are the same or different and eachindependently represents a hydrogen atom or a hydrocarbon group having 1to 8 carbon atoms and R⁴ represents an alkyl group, a cycloalkyl group,an aryl group, an aralkyl group or a silyl group.

In the formula (II), X¹, X² and X³ are the same or different and eachindependently represents a hydrogen atom, a halogen atom, an aminogroup, an alkyl group, an alkoxy group, a thioalkyl group, an alkylaminogroup, an aryl group, an arylamino group, an aralkyl group, a vinylgroup, or a heterocyclic group.

According to the present invention, there is also provided a method forpreparing the above-mentioned polyvinyl ether, which comprises allowing,in the presence of a catalyst composed of a polynuclearruthenium-carbonyl complex in which carbonyl groups coordinate with twoto four ruthenium atoms, a vinylether compound expressed by thefollowing formula (III)

(wherein R¹, R² and R³ are the same or different and each independentlyrepresents a hydrogen atom or a hydrocarbon group having 1 to 8 carbonatoms, and R⁴ represents an alkyl group, a cycloalkyl group, an arylgroup, an aralkyl group, a silyl group or a substituted derivativethereof)to react with a silane compound expressed by the following formula (IV):

(wherein X¹, X² and X³ are the same or different and each independentlyrepresents a hydrogen atom, a halogen atom, an amino group, an alkylgroup, an alkoxy group, a thioalkyl group, an alkylamino group, an arylgroup, an arylamino group, an aralkyl group, a vinyl group, or aheterocyclic group).

The most preferred polynuclear ruthenium-carbonyl complex as thecatalyst is a tri-nuclear ruthenium-carbonyl complex selected from amongthose expressed by the following formulae (V) and (VI), which containcoordinating acenaphthylene and coordinating azulene, respectively.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows examples of the polynuclear ruthenium carbonyl complex foruse as a catalyst in the present invention.

FIG. 2 shows an example of a GPC chart obtained with respect to apolyvinyl ether prepared in accordance with the present invention.

FIG. 3 shows the chemical formula of a polyvinyl ether prepared inaccordance with the present invention, together with a correspondingschematic formula from which NMR data can be assigned to the respectivepositions of the molecule.

FIG. 4 shows an example of an ¹H NMR spectrogram of a polyvinyl etherprepared in accordance with the present invention.

FIG. 5 shows an example of a ¹³C NMR spectrogram of a polyvinyl etherprepared in accordance with the present invention.

FIG. 6 shows an example of a GPC chart of the polymer synthesized inaccordance with the present invention using a silane having a phenylgroup.

FIG. 7 shows an example of a GPC chart of the polymer synthesized usinga silane not having a phenyl group.

BEST MODE FOR CARRYING OUT THE INVENTION

In FIG. 1 there are exemplified polynuclear ruthenium carbonylcomplexes, for use as a catalyst in the present invention, in whichcarbonyl groups coordinate with two to four ruthenium atoms. Such apolynuclear ruthenium carbonyl complex serves as a catalyst for thepolymerization of the vinylether compound, in the presence of the silanecompound, to produce the polyvinyl ether having a silicon-containingfunctional group at the terminal thereof, in which the polynuclearruthenium carbonyl complex catalyst is advantageous over cobalt carbonylcomplex catalysts such as Co₂(CO)₈ and platinum catalysts such asH₂PtCl₆·6H₂O, the conventionally well known polymerization catalysts, inthat it exhibits a higher activity even in a low catalyst concentrationwhile producing polymers with a narrow molecular weight distribution(cf. the working examples to be described later).

Particularly excellent and efficient catalysts for the polymerizationreaction of the vinyl ether compound in the presence of the silanecompound are tri-nuclear ruthenium-carbonyl complexes as expressed bythe formula 1 in FIG. 1 (the aforementioned formula (V)) and by theformula 5 in FIG. 1 (the aforementioned (VI)), containing coordinatingacenaphthylene and coordinating azulene, respectively. The promotion ofthe production of the polyvinyl ether having a silicon-containingfunctional group at the terminal thereof, by such polynuclear rutheniumcarbonyl complex, is presumably due to a structural change of thecoordinating acenaphthylene or azulene forming a conjugated π-electronsystem, which may cause displacement of the Ru atoms therebyfacilitating the introduction of Si atoms into the reaction system(Matsubara et. al., Organometallics, 21, 3023-3032 (2003)). By contrast,there is no such coordinating acenaphthylene or azulene in theaforementioned cobalt carbonyl compound or platinum compound.

According to the present invention in which the polymerization iscarried out with the above-mentioned polynuclear ruthenium carbonylcompound as the catalyst in the presence of the silane compound, it ispossible to produce the polyvinyl ether having a silicon-containingfunctional group or atomic group from a variety of known or availablevinyl ether compounds.

Thus, in the aforementioned formula (III) which expresses the startingmonomer, R¹, R² and R³ are generally a hydrogen atom but may eachindependently be selected from among a hydrogen atom and a hydrocarbongroup having 1 to 8 carbon atoms. The hydrocarbon groups having 1 to 8carbon atoms may include alkyl groups, aryl groups and aralkyl groups inwhich an alkyl group having 1 to 5 carbon atoms is particularlypreferred.

In the formula (III), R⁴ represents an alkyl group, a cycloalkyl group,an aryl group, an aralkyl group or a silyl group, in which suchfunctional groups may be substituted. The number of carbon atoms in thealkyl group, the cycloalkyl group, the aryl group or the aralkyl groupis generally, but is not limited to, in the range of 1 to 10. Theexamples of R⁴ include, but are not limited to, methyl group, ethylgroup, n-propyl group, isopropyl group, n-butyl group, isobutyl group,n-octyl group, cyclohexyl group, phenyl group, benzyl group,2-ethoxyethyl group, phenoxyethyl group, 2-chloroethyl group,trimethylsilyl group, and triethylsilyl group.

In preparing the polyvinyl ether having a silicon-containing functionalor atomic group in accordance with the present invention, there can beused a variety of known or available silane compounds. Thus, in theformula (IV) which expresses the silane compound, X1, X2 and X3 are thesame or different and each independently represents a hydrogen atom, ahalogen atom, an amino group, an alkyl group, an alkoxy group, athioalkyl group, an alkylamino group, an aryl group, an arylamino group,an aralkyl group, a vinyl group, or a heterocyclic group. The number ofcarbon atoms in such groups is generally, but is not limited to, 1 to18. A preferable example of the heterocyclic group is piridyl group.

According to the present invention, by allowing, in the presence of acatalyst composed of a polynuclear ruthenium-carbonyl complex such asthose expressed by the formula (V) or (VI), the vinyl ether compound toreact with the silane compound as mentioned above, there can be preparedthe polyvinyl ether composed of a repeating unit represented by theaforementioned formula (I) and having a hydrogen atom at one terminalthereof and a silicon-containing functional or atomic group representedby the aforementioned formula (II) at the other terminal thereof. Morespecifically the polyvinyl ether thus prepared can be expressed by thefollowing formula (VII):

For R¹, R² and R³ in the formulae (I) and (VII) and for X¹, X² and X³ inthe formulae (II) and (VII), the same definitions are applied to thesame symbolic letters as made with respect to the formulae (III) and(IV).

The molecular weight of the polyvinyl ether prepared in accordance withthe present invention is not restricted, but is generally in the rangeof approx, 500 to 500,000 as number-average molecular weight measured byGPC (gel permeation chromatography). Thus, n in the formula (VII)expresses a number (integer) corresponding to such molecular weight.

Therefore, the overall reaction scheme for the preparation of thepolyvinyl ether according to the present invention can be expressed bythe following reaction formula (VIII):

The reaction for the preparation of the polyvinyl ether according to thepresent invention, as expressed by the formula (VIII), can be carriedout under a mild condition, i.e. at atmospheric pressure at atemperature of 5 to 90° C. The reaction can be done either by a solutionpolymerization or by a bulk polymerization, between which the solutionpolymerization is more preferred. Examples of solvents suitable for usein the solvent polymerization include 1,4-dioxane, Tetrahydropyran,diethyl ether, tert-butyl methyl ether, and toluene. While the reactiontime depends upon such factors as the reaction temperature and thecatalyst concentration, it is generally in the range of one minute tofour hours.

EXAMPLES

While there are provided working examples below in order to more clearlydefine the features of the present invention, the present invention isnot in any respect limited by the working examples. Throughout thepresent specification and the drawings, Me denotes methyl group, Etdenotes ethyl group, Ph denotes phenyl group, Mn denotes number-averagemolecular weight, Mw denotes weight-average molecular weight, and GPCdenotes gel permeation chromatography.

Example 1 Syntheses of Polyvinyl Butyl Ether and Other Materials

Into a 30 ml round-bottom flask with two necks equipped with a three-waycock, in which the air had been replaced with nitrogen gas, there wereadded 2.15 mg (3.3×10⁻³ mmol) of acenaphthylene heptacarbonyl ruthenium(the polynuclear ruthenium-carbonyl complex as expressed by the formula(V): hereinafter sometimes referred to simply as the “Ru complex”) asthe catalyst, 0.05 ml of 1,4-dioxane as the solvent, and 0.050 ml (0.33mmol) of dimethylphenylsilane (HSiMe₂Ph) as the silane compound. Afterstirring at room temperature (25° C.) for thirty minutes, there wasadded 0.43 ml (3.3 mmol) of tert-butyl vinyl ether (tBuVE) as the vinylether compound. The resultant solution was stirred at room temperaturefor ten minutes, and then the 1,4-dioxane and the excess phenyldimethylsilane were distilled off. Into the residual viscous liquid wasdissolved in 2 ml of hexane. Following the addition of methanol 6 ml,the resultant white deposit was subjected to drying in vacuo, to yield awhite solid material, 277 mg (92%). The molecular weight of the whitesolid material was determined by GPC, and the material was alsosubjected to the measurement of IR, ¹H and ¹³C NMR spectra. FIG. 2 showsthe GPC chart. The assignment of the IR and NMR data are summarizedbelow. From these results the white solid material was identified to bepolyvinyl tert-butyl ether.

IR spectrum (KBr): 2979, 1474, 1389, 1362, 1253, 1230, 1195, 1105, 1059,1006 cm⁻¹.

¹H NMR spectrum: in C₆D₆, inner reference C₆H₆,

δ (ppm) 1.35(br, tBu), 1.96(br, CH₂), 3.88(br, CH).

¹³C NMR spectrum: in C₆D₆, inner reference C₆H₆,

δ (ppm) 29.7((CH₃)₃C), 46.1((CH₃)₃C), 66.9, 67.5, 68.1(CH₂), 72.8, 73.1,73.4(CH).

Isobutyl vinyl ether (iBuVE), n-butyl vinyl ether (nBuVE), or isopropylvinyl ether (iPrVE) was used instead of tert-butyl vinyl ether (tBuVE)as the starting monomer (the vinyl ether compound). The polymerizationreactions and the characterization of the formed polymer were carriedout in the same manner as mentioned above. The results are summarized inTable 1.

TABLE 1 Reaction Run time Conversion Yield No. monomer (min.) Mn Mw/Mn(%) (%) 1 iBuVE 60 10000 2.7 95 98 2 tBuVE 10 9000 1.4 96 92 3 nBuVE 12012000 2.1 96 82 4 iPrVE 20 10000 2.8 100 69 Monomer/Silane = 10:1Catalyst Concentration: 0.1 mol %

As shown in Table 1, all of the monomers (alkyl vinyl ethers) produced apolymer (polyvinyl ether) with a narrow molecular weight distribution (alow Mw/Mn).

Example 2 Comparison with Other Types of Catalysts

The polynuclear ruthenium-carbonyl complex catalyst according to thepresent invention was compared with the conventionally proposed cobaltcomplex catalyst and the platinum complex catalyst with respect tocatalyst performance for the polymerization reaction of the vinyl ether.The polynuclear ruthenium-carbonyl complex catalyst was the same Rucatalyst as used in Example 1, while the cobalt complex catalyst wasCo₂(CO)₈ and the platinum complex catalyst was H₂PtCl₆·6H₂O. Theprocedure of the reactions and the analysis of products were made in thesame manner as in Example 1. The polymerization reactions were carriedout at room temperature with tBuVE as the monomer (the starting vinylether) and HSiMe₂Ph as the silane compound in which the ratio of themonomer to the silane was 10:1. The results are summarized in Table 2.

TABLE 2 Reaction Catalyst Time Conversion Yield Complex (mol %) (hr) (%)(%) Mn Mw/Mn Ru Complex* 0.1 0.02 95 85 9000 1.2 Ru Complex* 0.01 4 8475 7000 2.3 Co₂(CO)₈** 0.1 0.1 100  84 7000 2.8 Co₂(CO)₈** 0.01 24 Noreaction Unmeasurable Unmeasurable Unmeasurable H₂PtCl₆.6H₂O*** 0.1 1Unmeasurable <10 Unmeasurable Unmeasurable H₂PtCl₆.6H₂O*** 0.01 24 Noreaction Unmeasurable Unmeasurable Unmeasurable *Solvent: THP (20 mol %)**Solvent: None ***Solvent: EtOH (20 mol %)

As shown in Table 2, the ruthenium complex used in the present inventionis very advantageous over the cobalt complex and the platinum complex inthat it is more reactive for the vinyl ether polymerization reactionthus producing, at a lower catalyst concentration, the polyvinyl ethereven with a narrow molecular weight distribution.

Example 3 Studies on Reaction Conditions

The polymerization reactions of iBuVE (isobutyl vinyl ether) werecarried out using the Ru catalyst in the presence of HSiMe₂Ph as thesilane compound in the same manner as in Example 1, at varying monomer(the vinyl ether compound)/silane (the silane compound) ratio andreaction temperature. The results are summarized in Table 3.

TABLE 3 Catalyst Reaction Reaction Run Monomer/ ConcentrationTemperature Time Conversion No. Silane (mol %) (° C.) (min.) Mn Mw/Mn(%) Yield 1  1:0.01 0.1 23 180 29000 6.5 24 36 2 1:0.1 0.1 23 60 100002.7 95 98 3 1:1   0.1 23 60 2000 2.1 91 61 4 1:0.1 0.1 60 40 6500 3.4 9982 5 1:0.1 0.1 80 40 4800 3.4 98 90

As can be seen from Table 3, it is possible to control the molecularweight and molecular weight distribution of the product polymer byvarying the monomer/silane ratio and the reaction temperature. Forexample, there can be obtained a polymer which has a relatively smallmolecular weight but has a narrower molecular weight distribution (lowerMw/Mn), by increasing the amount of the silane relatively over themonomer (the starting vinyl ether). It is also possible to produce apolymer having a larger molecular weight by lowering the reactiontemperature.

The polymerization reactions were further carried out in the same mannerusing different types of the silane (the silane compound). The resultsare summarized in Table 4. The monomer (the starting vinyl ether) wastBuVE for Run No. 6 and iBuVE for the other Runs.

TABLE 4 Reaction Con- Run Time Mw/ version Yield No. Silane (min.) Mn Mn(%) (%) 1 HSiMe₂Ph 60 10000 2.7 95 98 2 HSiMe₂Et 1 22000 3.4 98 96 3HSiMeEt₂ 5 13000 2.8 95 85 4 (HSiMe₂CH₂)₂ 120 4000 2.8 90 57 5 HSi(OEt)₃480 13000 2.5 100 78 6 HSiMe₂(CH═CH₂) 240 22000 1.6 92 78

Monomer/Silane=10:1,

Reaction Temperature: Room Temperature

Catalyst Concentration: 0.1 mol %

As can be seen from Table 4, according to the present invention in whichthe Ru complex was used as the catalyst, the vinyl ether polymerizationreaction proceeded efficiently with all types of the silane compounds.The product polymers had a narrow molecular weight distribution with aMn/Mn value of approx. 1.5 to 3.0, including the polymer with theextremely low value of 1.5 when tBuVE was used.

Example 4 Analysis of the Terminal of the Polymers

In order to study the terminal structure of the polymers prepared asabove, the product of Run No. 3 in Example 3 (the starting monomer:iBuVE, the silane: HSiMe₂Ph, monomer/silane=1:1, Mn=2000) was taken as arepresentative to be subjected to NMR analysis.

The NMR data are given below. In addition, FIG. 3 shows the chemicalformula of the product polymer (the polyvinyl ether), at the upper partof the figure, as well as a schematic structure of such polymer, at thelower part of the figure, from which the NMR data can be assigned to therespective hydrogen atoms and carbon atoms. FIG. 4 shows the ¹H NMRspectrogram while FIG. 5 shows the ¹³C NMR spectrogram. The respectivepositions denoted by the capital alphabetical letters in FIG. 4 and FIG.5 correspond to the respective positions denoted by the smallalphabetical letters in the formula shown in FIG. 3.

¹H NMR (C₆D₆, rt): δ 0.3(s, 6H, Ha), 7.55(d, 2H, Hb), 7.20(m, 3H, Hc andHd), 0.7-0.8(doublets, 2H, He), 1.2(m, 1H, Hf), 1.6-2.1(br, Hg),3.6-3.8(br, Hh), 3.0-3.4(br, Hi), 1.9(m, Hj), 0.99(brs, Hk), 3.4(t, 2H,Hm), 3.0(d, 2H, Hn), 1.2(m, 1H, Ho), 0.9(d, 6H, Hp).

¹³C NMR(C₆D₆, rt): δ −2.7(Ca), 134(Cb), 128(Cc), 131(Cd),136(ipso-PhSi), 4.9-6.0(Ce), 39-42(Cg), 74(Ch), 76(Ci), 29(Cj), 20(Ck),78(Cm), 67(Cn), 14(Cp).

Thus, from the ¹H NMR and ¹³C NMR spectral data it is evidenced that theproduct polymer is composed of the repeating units of iso-butyl ethergroup corresponding to the starting monomer and has a hydrogen atom atone terminal thereof and PhMe₂Si group corresponding to the silane atthe other terminal thereof.

The terminal structure of polyvinyl isobutyl ether prepared inaccordance with the present invention was also ascertained via GPC. Itis known that, in the case of a polymer having an UV-reactivesubstituent such as phenyl group within the repeating unit, the GPCprofile detected by UV detector resembles to that by RI detector. GPCdata for the polymer synthesized from the silane having a phenyl groupbound was therefore compared with GPC data for the polymer synthesizedfrom the silane not having phenyl group. As a result, it was ascertainedthat, only for the polymer from the phenyl group-containing silane, theGPC profile detected by UV detector resembles that by RI detector. FIG.6 shows the GPC chart of the polymer synthesized from the silane havinga phenyl group, whereas FIG. 7 shows the GPC chart of the polymer fromthe silane not having phenyl group.

INDUSTRIAL UTILIZABILITY

The present invention realizes, for the first time, the synthesis ofpolyvinyl ether having a reactive silicon-containing functional oratomic group at the terminal thereof. The polyvinyl ether obtained inaccordance with the present invention will contribute to the developmentof novel materials with new characteristics, as it is easy to bind thepolymer with another type of compound (molecule) by modifying thereactive silicon-containing functional or atomic group thereof toanother type of functional group. The present invention is also of greatsignificance in that it enables the production of polymers with a narrowmolecular weight distribution, which is one of the highly demandedproperties for a polymer for industrial use

1. A polyvinyl ether composed of a repeating unit represented by thefollowing formula (I) and having a hydrogen atom at one terminal thereofand a silicon-containing functional group or atomic group represented bythe following formula (II) at the other terminal thereof:

wherein R¹, R² and R³ are the same or different and each independentlyrepresents a hydrogen atom or a hydrocarbon group having 1 to 8 carbonatoms and R⁴ represents an alkyl group, a cycloalkyl group, an arylgroup, an aralkyl group, a silyl group, or a substituted derivativethereof

wherein X¹, X² and X³ are the same or different and each independentlyrepresents a hydrogen atom, a halogen atom, an amino group, an alkylgroup, an alkoxy group, a thioalkyl group, an alkylamino group, an arylgroup, an arylamino group, an aralkyl group, a vinyl group, or aheterocyclic group.
 2. A method for preparing the polyvinyl ether asdefined by claim 1, which comprises allowing, in the presence of acatalyst composed of a polynuclear ruthenium-carbonyl complex in whichcarbonyl groups coordinate with two to four ruthenium atoms, avinylether compound expressed by the following formula (III) to reactwith a silane compound expressed by the following formula (IV):

wherein R¹, R² and R³ are the same or different and each independentlyrepresents a hydrogen atom or a hydrocarbon group having 1 to 8 carbonatoms, and R⁴ represents an alkyl group, a cycloalkyl group, an arylgroup, an aralkyl group, a silyl group or a substituted derivativethereof

wherein X¹, X² and X³ are the same or different and each independentlyrepresents a hydrogen atom, a halogen atom, an amino group, an alkylgroup, an alkoxy group, a thioalkyl group, an alkylamino group, an arylgroup, an arylamino group, an aralkyl group, a vinyl group, or aheterocyclic group.
 3. A method of preparing the polyvinyl ether asdefined by claim 2, in which the polynuclear ruthenium-carbonyl complexis a tri-nuclear ruthenium-carbonyl complex selected from among thoseexpressed by the following formulae (V) and (VI), which containcoordinating acenaphthylene and coordinating azulene, respectively